As people have said you won't need a car in the city. Plenty of taxi's, uber, subway which we call the T. This is an awesome city, especially if you're a history buff. Roxbury can be a rough area of town at night though. Everything is more expensive in this state.
things to do?: New England Aquarium, Museum of Science, Duck tour, Freedom Trail, Faneuil Hall, Franklin Park Zoo (during the day), North End and the North End Church, Fenway Park, Boston Garden, Foxborough Stadium (Go Pats!) is about 25-30 minutes from the city but they have a huge shopping and bar/resturaunt scene around the field- fun time even if no game happening. We have tons of eateries but very scarce on BBQ. You will have some of the best clam chowder you've ever had here. (Unless you like that crap made with tomato- Farkin New yorkers) ((everything New York sucks!!!))